1. Field of the Invention
This invention relates to a water-proof camera of the type in which a hinge type back lid is opened when a film is loaded and is closed after the film has been loaded, and more particularly to such a water-proof camera having a water-proof device which provides, during the closing of the back lid, crushing tolerance in thrust direction to an elastic water-proof packing acting to water-proof the back lid.
2. Description of the Prior Art
Heretofore, loading of a film into a water-proof camera has been accomplished by taking the mechanism portion of the camera body out of the housing of the camera body instead of opening and closing a hinge type back lid as when a film is loaded into an ordinary camera. Of course, the coupling portion therebetween is provided with a water-proof packing. Accordingly, the procedure of loading a film into a water-proof camera is very cumbersome as compared with the case of the ordinary cameras and therefore, it is desired in the water-proof camera that a film can be loaded by opening and closing the hinge type back lid which is easy to manipulate. In this case, however, water-proof means becomes a problem to be considered. On the other hand, an O-ring is usually used as the water-proof means in a water-proof camera. As the manner of using such O-ring, it is usual to use it while holding it down in radial direction. In this case, oil must be used for the O-ring and this leads to a disadvantage that the O-ring becomes swollen due to the oil or that due to degeneration of the oil, a great force is required to take the mechanism portion of the camera body out of the housing of the camera body or that the O-ring becomes distorted by taking in and out of the mechanism portion of the camera body and the service life of the O-ring is shortened. As a manner of using an O-ring which is intended to overcome these disadvantages, there may be mentioned an example in which the O-ring is used while being held down in thrust direction. In such case, the O-ring must be pushed with a predetermined force to provide for a crushing tolerance of the O-ring. For this purpose, U.S. Pat. No. 3,831,182 discloses a water-proof camera which includes a hinge type back lid openable and closable with respect to the camera body, an auxiliary back lid and an elastic member disposed therebetween and wherein when the hinge type back lid is closed, the elastic member biases the auxiliary back lid toward the camera body side, as a result of which an O-ring is held down in thrust direction between the auxiliary back lid and the camera body.
However, in this prior art, the hinge type back lid and the auxiliary back lid are formed as a double structure and this leads to a disadvantage that the thickness of the camera body is increased when the back lid is closed or that during the opening of the back lid, the elastic member may be plastically deformed by the auxiliary back lid being pulled or pushed out by mistake with a result that the back lid cannot be closed or that the O-ring cannot be held down in the thrust direction expected in the stage of design.